In known fuel systems for automobiles, a refueling inlet pipe extends from a fuel tank to an accessible location on the outside of the vehicle. It is known to provide a housing near the outer end of the refueling inlet pipe for holding the distal end of the pipe into which a refueling nozzle from a refueling pump can be inserted for refueling. A door or other housing closure may be provided to protect the distal end of the pipe. Known fuel system housing designs are made of hard plastic, such as glass filled polypropylene, and are configured to be installed into sheet-metal body panels of the vehicle at both the inner and outer ends of the housing. Generally, both the inner and outer edges of the fuel housing are sealed to the vehicle body sheet metal panels.
It is known to provide seals for the inner and outer edges of a fuel housing as integral portions of the fuel housing assembly by including a thermoplastic elastomer overmolded on the inner and outer ends of the housing. The fuel housing is first molded as a so-called “hard shot” of plastic, and the seals are then formed as so-called “soft shots” that are overmolded onto the housing to form an integral unit of the hard housing and the softer seals. As known to those skilled in the art, so-called “overmolding” is a two-shot molding process which first molds a first component of a first material. The molded component is loading to an injection mold tool cavity and a second shot, typically of a second material different from the first material, is molded around designated areas of the first component to form a bond between the two materials.
It is known to provide the hard shot or housing body with integrated snaps at the outer edge of the housing for attaching the housing to the outer sheet-metal panel. The housing body also provides rigidity to the fuel housing system that supports a hinge arm which holds the fuel door in position as it is opened and closed during the refueling of a vehicle.
Accordingly, a vehicle fuel system housing has two areas to be sealed during assembly. The overmolded soft shot perimeter seal or outer perimeter seal seals to an outer sheet metal panel, and the overmolded inner seal seals to a fuel pipe and to an inner sheet metal panel. While generally performing well, constructions of known designs have been somewhat difficult to install, particularly in positioning the inner seal properly. If proper seals are not established, it is possible that water will leak into the vehicle or that fuel vapors will enter the interior of the vehicle.
In a known design for a fuel housing assembly, the inner seal utilizes only a soft shot which, due to its soft and compliant characteristics, can be difficult to install into the vehicle inner sheet metal and difficult to manipulate into position to form a good seal to the inner sheet metal. It is known to form the soft overmolded inner seal with parallel circumferential ridges on the exterior surface. The seal is inserted through an opening in the sheet-metal, with the first encountered of the aforementioned parallel circumferential ridges being forced through the opening so that the sheet-metal edge resides in a valley between the parallel circumferential ridges. To achieve this positioning, it has been necessary in some installations to work from both sides of the sheet-metal body, both inside and outside the vehicle to manipulate the seal. This can be both difficult and time consuming.